Permanent Tissues Essay

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Permanent tissues Simple permanent tissues Parenchyma It consists of relatively unspecialised cells with thin cell walls. They are live cells. They are usually loosely packed, so that large spaces between cells(intercellular spaces)are found in this tissue. This tissue provides support to plants and also stores food.In some situations, it contains chlorophyll and performs photosynthesis, and then it is called chlorenchyma. Collenchyma It is a living tissue of primary body like Parenchyma. Cells are thin-walled but possess thickening of cellulose and pectin substances at the corners where number of cells join together. This tissue gives a tensile strength to the plant and the cells are compactly arranged and do not have inter-cellular spaces. It occurs chiefly in hypodermis of stems and leaves. It is absent in monocots and in roots. Sclerenchyma This tissue consists of thick-walled, dead cells. These cells have hard and extremely thick secondary walls due to uniform distribution of lignin. Lignin deposition is so thick that the cell walls become strong, rigid and impermeable to water. Sclerenchymatous cells are closely packed without inter-cellular spaces between them. Epidermis The entire surface of the plant consists of a single layer of cells called epidermis or surface tissue. The entire surface of the plant has this outer layer of epidermis. Hence it is also called surface tissue. Most of the epidermal cells are relatively flat. the outer and lateral walls of the cell are often thicker than the inner walls. The cells forms a continuous sheet without inter cellular spaces. It protects all parts of the plant. Complex permanent tissue Xylem Xylem is a chief, conducting tissue of vascular plants. It is responsible for conduction of water and mineral ions. Phloem phloem carries dissolved food substances throughout the plant. This conduction system is

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